The grandmother (spoilers)

I felt she was slightly insignificant to the film because it establishes her early on as this magical guardian over Irene and the castle, yet all she does is give Irene a ring to help her find her way into and out of the goblin kingdom. Nothing she contributes really helps Irene battle the goblins in the end because Irene ends up playing the damsel in distress and only helps beat Froglip by learning what Curdie showed her. So when the last scene in which we hear the King narrate of how he knew the grandmother was watching over all of them, that last line and shot of the flashing window really didn't add up to the whole of the film because she and her magic barely contributed to the whole clash between the sun people and the goblins. In a way, the film didn't need a magical being to aid against the goblins because the goblins had no magic powers of their own, they turned out to be really goofy and incompetent creatures who got beat so easily with stamps on their feet and kicks in the chests, there was no need for magic. So why did the grandmother exist in the first place? She seemed like she belonged in a different story, like Galadriel in LOTR, only she had more to contribute in that story.